The invention relates to an optical rangefinder as used, for example, in surveying plots of ground and structures.
Optical rangefinders of the generic type have long been known. However, the luminance of the usually used emitters having a laser diode as a light source is as a rule lower than will be permissible from the point of view of eye protection. Moreover, the light beam emitted by an individual laser diode usually has a disadvantageous, very elongated cross-section, which can lead to insufficient focusing onto the target and consequently to an inadequate luminous flux and measuring errors. For these reasons, the range and accuracy of measurement and reliability of measurement of rangefinders of the generic type will be less than desirable and in principle also possible.
It is the object of the invention to provide an optical rangefinder of the generic-type whose emitter has a high luminance and ensures good target illumination and high luminous flux at the target.
The advantages achieved by the invention lie in particular in a decisive improvement in the range, i.e. in the maximum measured distance or, for a given range, an increase in the accuracy of measurement. These advantages are achieved with a relatively small emitter optical system, which makes it possible to keep the dimensions of the entire device small.